Mutants deficient in aspartate/glutamate transport were isolated by their resistance to threo-hydroxy-aspartate. The mutant is being mapped by transduction; so far we know that the marker is close to the argC gene. Attempts are underway to isolate the carrier protein by the use of N-thylmaleimide labelling or affinity chromatography. The inhibition of growth by hexachlorophene is investigated and compared to the effect of decanoate which has previously been shown to uncouple amino acid transport from the electron transport system of B. subtilis. Both compounds inhibit oxygen consumption, ATP synthesis, and amino acid uptake in whole cells indicating that they both act by uncoupling. However, complications were encountered when glucose or malate were used as additional carbon source; these are being investigated.